elementary map and aerial photograph reading

141 Pages·2007·5.35 MB·English

Copy 3M ANUAL
WAR DEPARTMENT FIELD MANUAL
ELEMENTARY MAP AND
AERIAL PHOTOGRAPH
READING
WAR DEPARTMENT - 15 AUGUST 1944
WA R DEPAR TMEN T FIELD MA N UA L
FM 21-25
This mnainual supersedes FM 21-25, 12 April 1941, including C 1, 17 Jan-
uary 1942, C 2, 20 April 1942, and C 3, 19 June 1942.
ELEMENTARY MAP AND
AERIAL PHOTOGRAPH
READING
WAAR DEPARTMENT 15 A UGUST 1944
For sale by the Superintendent of Documents, Washington 25, D. C.
WAR DEPARTMENT,
WASHINGTON 25, D. C., 15 August 1944.
FM 21-25, Elementary Map and Aerial Photograph
Reading, is published for the information and guidance
of all concerned.
[A. G. 300.7 (I Jul 44).]
BY ORDER OF THE SECRETARY OF WAR:
G. C. MARSHALL,
Chief of Stagf.
OFFICIAL:
J. A. ULIO,
Major General,
The Adjutant General.
DISTRIBUTION:
As prescribed in paragraph 9a, FM 21-6 except Ch of Engr
(500), Engr Board (50), Engr Sch (2000), Sv C (100), Depts
(100), Armies (100), Corps (50), D(50); B(50); R(25); Bn
(20); C(20); T of Opns (100); Island Comds (100); Bar:e
Comds (100); Def Comds (100); Sectors (50); Sub Sectors (25);
Tng Centers and Schs having no co orgn, ea off and enl pers (1);
additional copies may be requisitioned per WD Cir 264, dated
28 June 1944, on basis of (1) per individual.
(For explanation of symbols, see FM 21-6.)
CONTENTS
Page
CHAPTER 1. Why Learn to Read a Map? ............. 1
CHAPTER 2. What Is a Map? ................... 4....
CHAPTER 3. What Is On a Map?................... 10
CHAPTER 4. How High Is It? ...................... 22
CHAPTER 5. How Far Is It? ........................ 34
CHAPTER 6. Where Is It? .......................... 42
CHAPTER 7. Which Way Is It? ..................... 52
CHAPTER 8. Two Ways to Line Up Your Map with
the Ground ........................ 62
CHAPTER 9. Your Map and Compass Go to Work.... 72
CHAPTER 10. On the Road .......................... 90
CHAPTER 11. Aerial Photographs and Photomaps ...... 92
CHAPTER 12. The Army On the Map ................ 105
CHAPTER 13. Taking Care of Your Map .............. 116
i
Figure 1.
Figure 2.
LvrPd r ~ s'-" '
iA _
This manual supersedes FM 21-25, 12 April 1941, including C 1, 17
January 1942, C 2, 20 April 1942, and C 3, 19 June 1942.
CHAPTER 1
WHY LEARN TO READ A MAP?
In civilian life it is possible for a stranger to find his
way around a large city or town by merely asking direc-
tions. Any policeman or friendly native of the town
can supply enough information so that the stranger can
locate the street or building he wants. He may have to
overcome a few wrong directions thrown in with the
right ones, but he is sure of finding his way.
In war an army often finds itself in strange country,
but often it does not find friendly people everywhere,
ready and able to help it find its way. As a soldier in
the army, you will have to ask directions like any other
stranger, but you will ask your map. Your map has all
the answers if you are able to read it, and if you can read
it, it is one of your best friends.
There are lots of times in the army when you will
need this friend. The two soldiers in figure 2 are using
it to find their way to headquarters. They are mes-
sengers and they carry important news, but without
knowing how to read and use a map they would never
get there.
When you are on a patrol you and your detail are on
your own. At times you may be entirely alone and a
map will be your most trusted friend and guide. Re-
ports from men in combat show that every man must
know how to read and use a map if he wants to stay
alive and keep his outfit safe.
I
Figure 3.
If a vehicle takes a wrong turn the result isn't always
pretty. Look at the pictures in figures 4 and 5. That
happened because someone did not know how to read a
map and use his compass. The drivers had both a map
and a compass, but that was not enough. They did not
know how to use them.
A native of a place can tell us lots of things to help us,
but we have to be able to speak his language. In that
way, a map is no different from a native. We must
learn to read and understand the language of a map. It
is a simple and clear language. You will use it very
often in the army, many times when you are in a tight
spot. If you learn to use it correctly, it won't let you
down.
2
Figu r--.
Figure 4.
Figure 5.
CHAPTER 2
WHAT IS A MAP?
A map is a picture. It isn't a puzzle and it isn't hard
to read. It is a picture of the land and the things people
have built on the land.
There are really only two things about a map which
make it a little strange to read. In the first place, a map
is flat and when we look at a map we are looking at a
picture of the ground from a spot high in the air. That
view is different from the one we have looked at all our
lives, from one point on the ground to another point on
the ground. So the first thing we must do is to under-
stand where we sit when we look at this picture.
To give us an idea of what happens when we look at
something from above, let's watch a football game and
see what happens when we look at it from different
seats. If we are on the player's bench, we see a picture
like the one in figure 6.
Figure 6.
4r U
4
Figure 7.
From the grandstand, we see things a little differently.
The game looks something like the one in figure 7. If
we climb into a blimp and rise up above the edge of the
stadium, we see the game as in figure 8.
Now if our blimp takes us directly over the playing
Figure 8.
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